<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="utf-8">
    <title>太极</title>
    <link rel="stylesheet" href="../../common/reset.css">
    <style>
        .box {
            margin: 40px auto;
            box-sizing: border-box;
            width: 0;
            height: 0;
            border-radius: 50%;
            border-top: 100px solid #fff;
            border-right: 100px solid #000;
            border-bottom: 100px solid #000;
            border-left: 100px solid #fff;
            box-shadow: 0 0 1px 1px #000;
            position: relative;
            transform: rotate(44deg);
        }
        
        .box::before {
            content: "";
            width: 30px;
            height: 30px;
            background-color: #fff;
            border: 36px solid #000;
            border-radius: 50%;
            position: absolute;
            top: -81px;
            left: -11px;
        }
        
        .box::after {
            content: "";
            width: 30px;
            height: 30px;
            background-color: #000;
            border: 36px solid #fff;
            border-radius: 50%;
            position: absolute;
            bottom: -92px;
            right: -22px;
        }
    </style>
</head>

<body>

    <div class="box"></div>

</body>

</html>